This invention pertains generally to the field of x-ray and neutron multi-fiber polycapillary optics, and more particularly, to a novel support structure for a polycapillary optic.
Conventionally, multi-fiber polycapillary optics are constructed by positioning screens (containing precise hole patterns) each onto a separate stiff screen holder. These constructions are then used to position glass fibers in space as described in U.S. Pat. No. 5,192,869. As seen in FIG. 1, a screen 18 is located relative to a screen holder 14 by pressing two locating pins therebetween. The screens have two holes 10 that align with the pins in the screen holder. The screen holders are then assembled together using precision rods 12 to locate each screen holder relative to the other in an x,y coordinate system. Positioning in the z direction is achieved by using spacers 16 between each screen holder. Up to four separate types of rods are thus used to precisely position the screen holders of the assembly.
A drawback of the above-summarized structure is that systematic errors associated with assembly of the screens to the screen holders may occur, as well as the screen holders to each other and to other components in the chain. As an example, the optic assembly of FIG. 1 uses four screens directly mounted to four screen holders, and separated by three independent pairs of spacers. Tolerance stack-ups associated with the mounting of the screens to frames and subsequent alignment of the system can result in large, uncontrollable tolerance errors. Thus, the resultant optic is susceptible to mis-alignment due to the inefficient way that the housing assembly is fastened together.
Further, it should be noted that the above-described approach employs screen holders which are aligned by two axes, i.e., by rods 12. Alignment using two axes results in five degrees of freedom (i.e., three translation, and two rotation) that can result in misalignment of the screen holders relative to each other. Additionally, there are four items that require tight tolerance control for each screen and screen holder combination. These include the holes in the screen holders for the rods and the two holes in each of the screen and screen holder for the locating pins.
Based upon the above, there exists a need in the art for an improved support device for a polycapillary optic.
Briefly summarized, presented herein is a novel support device for a polycapillary optic. The support device includes a housing having a central opening passing therethrough with at least two locating structures formed within the housing adjacent to the central opening and aligned about an axis of the central opening. Each locating structure is sized and positioned to accommodate a polycapillary positioning component within the housing. The at least two locating structures are formed such that the polycapillary positioning components can be oriented transverse to an axis of the central opening. The at least two polycapillary positioning components are designed to hold one or more polycapillaries of the polycapillary optic such that radiation from one of a divergent beam, a focused beam, or a parallel beam can be collected by the optic, and such that the optic can output one of a collimated beam, a focused beam or a divergent beam depending upon the configuration of openings in the polycapillary positioning components, as well as the positioning and orientation of the components within the housing.
Those skilled in the art will note from the following description that a support device and polycapillary optic assembly in accordance with this invention provide numerous advantages over the polycapillary positioning art, including: providing-higher repeatability of optic quality; being easier to assemble, and therefore less expensive to produce; having fewer components and a smaller total size, i.e., of the assembled x-ray optic package; elimination of positioning and assembly errors; ruling the assembly out as the problem if the resultant optic exhibits poor performance; reducing any possibility of components becoming loose, and the resulting misalignment of polycapillaries; facilitating use of the housing to align the resultant optic to a source, detector or sample; providing a greater ability to control tip, tilt and translation of the optic relative to a source, detector or sample; providing better control of rotation of screens relative to each other; reducing error associated with assembly and tolerance stack up; using a precise bore defining the inner opening as a means to accurately position the polycapillary optic relative to a radiation source or output location; and, in general, producing higher quality optics by improving radiation beam uniformity, focal spot and beam divergence characteristics.